The invention relates to a method for cleaning the filters of a vacuum cleaner which has a dirt collecting container with a suction inlet, to which a suction tube is connected, the dirt collecting container being in connection with at least one suction unit via at least one filter and at least one suction line following the latter, and at least one closing valve closing an external air inlet, via which the suction line is connected to an external air supply, and in which method, for cleaning the at least one filter, at least one closing valve is opened and the side of the at least one filter that is oriented away from the dirt collecting container is impinged upon by external air.
The invention also relates to a vacuum cleaner for carrying out said method.
By means of the vacuum cleaner in question here, dirt and preferably also liquid can be sucked up by using at least one suction unit to apply negative pressure to the dirt collecting container, so that a suction flow forms. The vacuum cleaner has one or more filters, which are disposed in the flow path from the dirt collecting container to the at least one suction unit and serve for separating solid substances from the suction flow. During suction operation, dirt particles are increasingly deposited on the side of the at least one filter that is oriented toward the dirt collecting container, so that after some time the filter or filters have to be cleaned. For cleaning, the side of the filter that is oriented away from the dirt collecting container can be impinged upon by external air, by opening at least one closing valve, so that external air can flow into the at least one suction line via the external air inlet.
For cleaning a filter, it is proposed in DE 298 23 411 U1 to close the suction tube for a short time, so that a strong negative pressure forms in the dirt collecting container, and a closing valve is subsequently to be opened for a short time. The filter is then flowed through by the external air in the direction of counterflow, that is to say counter to the direction of the suction flow, so that dirt particles adhering to the filter become detached. This allows effective cleaning of the filter to be achieved, but the suction operation has to be interrupted by the user for this purpose.
In DE 199 49 095 A1, it is proposed to use two filters, which are cleaned alternatively, it being possible during the cleaning of one filter for the suction operation to be continued to a restricted extent by means of the other filter. However, this requires a complex construction, the two filters having to be of a considerable size to permit adequate suction flow during restricted suction operation. Furthermore, the alternative cleaning of one filter at a time while at the same time maintaining the suction operation by means of the other filter is prone to faults.
It is an object of the present invention to provide a filter cleaning method for a vacuum cleaner in which all the filters present can be flowed through by suction air during suction operation, but suction operation does not have to be noticeably interrupted for the user for filter cleaning.